After her parents' deaths, college student Mahiru lives with her three stepbrothers who dote on her daily. One day, she receives news that her estranged grandfather has passed away... and his assets total 15 billion yen. In his will he writes, "Among the three of you, will there be one who'll be able to be with Mahiru? If you choose to kill her, then the one who does so will receive all my inheritance."